Unsubbed in WoD, stopped actually playing in MoP. MoP was so awfully linear and boring I stopped playing as much as I used to and stopped raiding because raids were just not interesting and I didn't care about the story. Got hyped a bit before WoD, even went onto a raiding spree for a couple of weeks with the guild and was disappointed with raids again (ok, Garrosh was kind of fun but still meh). Quested through WoD once, tried the Highmaul raid, unsubbed the next week.
In fact WoD was the moment when I finally realized how far the game went from me enjoying it to simply becoming a habit. Cataclysm was the expansion when I started to lose interest in the game. While WoTLK and TBC brought many changes that I though to be questionable, I still enjoyed the game, in Cata the amount of the questionable changes became just too high but I kept playing because of the guild and, again, WoW became sour of a habit at that point.